High density lipoproteins with differing apolipoproteins: relationships to postprandial lipemia, cholesteryl ester transfer protein, and activities of lipoprotein lipase, hepatic lipase, and lecithin: cholesterol acyltransferase

To gain insight into metabolic determinants of high density lipoproteins (HDL) containing apolipoproteins A-I and A-I1 (LpA-I/A-11) and those containing A-I, but devoid of A-I1 (LpA-I), the plasma concentration of LpA-I and LpA-I/A-I1 wi- thin the HDLz and HDL3 density spectrum was measured in 14 normolipidemic male subjects on a standardized diet. Apolipoprotein plasma concentrations of HDL subspecies were compared with the magnitude of postprandial lipemia, activities of lipoprotein lipase and hepatic lipase in postheparin plasma, plasma 1ecithin:cholesterol acyltransferase (LCAT) activity, and cholesteryl ester transfer protein (CETP) mass. Plasma levels of LpA-I/A-I1 were 2.5 times higher than levels of LpA-I (123 + 20 vs. 48.3 f 22.1 mg protein/dl) and the partition of LpA-I and LpA-I/A-I1 between HDLz and HDL3 differed in that the proportion of LpA-I associated with HDLZ was greater than that of LpA-I/A-I1 (23 f 19 vs. 6 6%, P < 0.002). With increas- ing levels of HDLZ, the proportion of LpA-I in HDLZ increased (P < 0.002). Furthermore, levels of LpA-I and LpA-I/A-I1 were strongly correlated within the HDLZ, but not within the HDLS density region. Plasma levels of LpA-I, but not LpA-I/A-11, were inversely correlated with the magnitude of postprandial lipemia. However, activities of lipoprotein lipase and hepatic lipase tended to show stronger associations with the partition of LpA- I/A-I1 between HDLz and HDL3 than with that of LpA-I. Wi- thin the HDL,, but not the HDLZ density spectrum, LpA-I/A-I1 exhibited a positive association with plasma LCAT activity, while LpA-I displayed an inverse association with plasma CETP mass. I These results are consistent with differences in sub- strate properties of LpA-I and LpA-I/A-I1 for lipoprotein- modifying enzymes and imply different, but overlapping meta- bolic pathways of LpA-I and LpA-I/A-11.-Mowri, H-O., J. R. Patsch, A. Ritsch, B. Foger, S. Brawn, and W. Patsch. High density lipoproteins with differing apolipoproteins: relationships to postprandial lipemia, cholesteryl ester transfer protein, and activities of lipoprotein lipase, hepatic lipase, and leci- thin:cholesterol acyltransferase. J. Lipid Res. 1994. 35: 291-300.